Anti-hiperglycemic Effect of Urena lobata Leaf Extract by Inhibition of Dipeptidyl Peptidase IV ( DPP-IV ) on Diabetic Rats

Abstract

Glucagon Like Peptide-1 (GLP-1) is one of incretin hormone which is proposed as a new therapy for type 2 diabetes (T2DM). However, this hormone is metabolized excessively by Dipeptidyl Peptidase IV (DPP-IV) into inactive form. The inhibition of DPP-IV can prolong GLP-1 bioavailability for regulating blood glucose level on T2DM. Urena lobata is a plant which has been used to cure T2DM empirically but the inhibitory activity on DPP-IV has not been tested. The aim of the study was to evaluate anti diabetic effect of U. lobata leaf extract through DPP-IV inhibition. Urena lobata leaf was extracted in ethanol solvent and hot water then evaporated till pasta form. The object study was used animal model of T2DM which divided into 2 control group and 6 test group (n=4) and then DPP-IV level, GLP-1, insulin and blood glucose AUC were examined after supplemented U. lobata leaf extract. All data are expressed as the mean ± SD and analyzed with one way anova and then continued with LSD and Dunnet c (p<0.05). Both of water and ethanolic extract from U. lobata decrease DPP-IV level and blood glucose AUC compared to control group (p<0.05) whereas insulin level and GLP-1 are increased (p<0.05). It was controlled by stigmasterol, β-sitosterol and mangiferin having anti-diabetic effect by inhibiting DPP-IV. Water extract of U. lobata stronger decrease DPP-IV level and blood glucose AUC and also increase insulin level and GLP-1 compared to ethanolic extract (p<0.05). The conformation change of active substances result a poor solubility and absorption in ethanol extract contribute to decrease their biology activity.